1. Technical Field
The present disclosure relates to a system and method for providing inboard exhaust in a V-type, pushrod or cam-in-block internal combustion engine.
2. Background Art
Engine compartments of automotive vehicles have grown increasingly crowded as more components are added to the engine to improve performance and reduce emissions. V-type turbocharged engines may include a pushrod valvetrain having the camshaft located in the engine block, and the turbocharger(s) located in the valley formed between the two cylinder heads to provide a compact engine package. However, conventional outboard exhaust manifolds require relatively long runners to route the exhaust to the turbocharger located in the valley. This increases the package size and increases heat rejection associated with greater exposed surface area resulting in higher underhood temperatures and longer catalytic converter light-off times. It is desirable for packaging considerations, turbocharger efficiency, and catalytic converter light-off times to reduce the complexity and length of the exhaust plumbing. Reduced package size generally improves heat retention and turbo boost and operating efficiency.
A central or inboard exhaust configuration may be used to reduce exhaust runner length to the turbocharger. This configuration has the exhaust ports of each cylinder bank directed inboard toward the valley of the engine. While such an arrangement significantly reduces the length of the exhaust runners, the exhaust must be routed around the pushrods and cylinder head bolts. In addition, the increased heat in the valley presents challenges with respect to the configuration of the water jacket for sufficient coolant flow to prevent oil coking and/or warping or cracking of the cylinder heads. Other heat-related and packaging considerations include positioning of the high-pressure fuel pump for common rail fuel injection systems.